Fig. 4

mespaa mutant embryos do not display defects in cardiac specification but exhibit abnormalities in left-right asymmetry. (A) Schematic of the mespaa^hsc11 null allele that was generated. (B-C) Whole embryo morphology of WT and mespaa^hsc11 null mutants at 48 hpf. (D-E) nkx2.5 expression in WT and mespaa^hsc11 null embryos at 16 hpf. (F-G) myl7 expression in WT and mespaa^hsc11 null embryos at 48hpf. (H-I) Normal and reversed heart looping demonstrated with myl7 expression at 48 hpf. A demarcates the atrium and V indicates the ventricle. (J) Percent of embryos displaying normal or reversed heart looping when deficient for different Mesp family members alone or in combination when compared to WT. (K-N) The four categories of lefty1/2 expression observed in WT and Mesp deficient embryos. (O) Percent of embryos displaying the different lefty1/2 expression patterns in WT and Mesp deficient embryos.